RFIC architectures 3. S-parameters and impedance transformation 4. RF basics 5. Transistors and technologies 6. Passive devices 7. Amplifier basics 8. Low noise amplifiers 9. Power amplifiers Mixers Oscillators If these topics are new for you, please study them in advance, e.
The exam review will take place on 4. The current schedule version The number of seats is limited, please enroll early, especially when the lecture is a compulsory subject for you!
There must be change to convey a message. If the signal consisted of 1 0 1 0 1 0 1 0. So while change is important, it is not the sole criterion for informa- tion.
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There is one last example. It is simply noise, and the receiver becomes no more knowledgeable upon having heard it. A communication system consists of a transmitter, a receiver, and a channel. The channel is capable of carrying only a certain limited amount of information. Roughly analogous to an information channel is a water pipe which, because of its diameter, is restricted to carrying only a certain amount of water. The time interval can be broken up into shorter time intervals, each of duration. Clearly, the more distinct time intervals these are in the total time span T, the more information can be transmitted.
PCB layout for high frequency or radio frequency (RF) circuit
The minimum size of is determined by how well one pulse in one time frame can be distinguished from a pulse in a neighboring time frame. The limitation on how short a time frame can be is related to the channel bandwidth. In addition the signal voltage will have a maximum amplitude that is limited by the available power in the system. This voltage range can be divided into many levels, each level representing a bit of information that is distinguished from another bit. Clearly, the more voltage intervals there are in a given time frame , the more information capacity there is in the system.
In one of the time intervals, , there are n voltage levels. The smaller that is and the larger that n is, the more information there can be transmitted through the channel. In each time interval there are n possible voltage levels. In the next time interval there are also n possible voltage levels.
It is assumed that the voltage By convention, the base-2 logarithm is used. Furthermore, as the number of voltage levels increases, so does the capacity for more information. Information can be transmitted through a channel in a variety of different forms, all producing the same amount of information. For example, suppose that a signal can take on any one of eight different voltage levels, 0, 1,. But the eight signal levels could also equally be sent with just two levels, 0, 1. For every interval that has eight possible levels, three intervals will be needed for the two-level signal.
A convenient conversion between the two systems is shown in Table 1. For n levels, log2 n bits are needed. A system is designed to transmit speech must be designed to have the capacity to transmit the information contained in the speech. While speech is not entirely what humans communicate, in a communication system it is what engineers have to work with. This translates to the bandwidth requirement of an analog system, or the number of voltage levels available in a given total voltage range. Ultimately this restriction is always present even if sophisticated coding techniques are used.
Beyond this capacity, system cost, power levels, and available transmission media must be considered. However, one simple example where this is not the case is the transmission of the English language. It is known that in the English language the letter e appears more frequently than the letter z. It is almost certain that the letter q will be followed by the letter u.
So, in transmitting a typical message in English, less information is actually sent than would be sent if every letter in the alphabet were equally likely to occur. A way to express this situation is in terms of probability. The probability takes the form P D number of occurrences of a particular event total number of events 1. For any one event, the information transmitted is written H1 D log2 P.
For m intervals, each seconds long, there will be m times more information. So for m intervals, the information written in terms of probability is H D T log2 n D m log2 P bits 1. If, for example, p D 0. As p approaches 1 and q approaches 0, the near certainty of event with probability p will give 0 information. The maximum information occurs when p D q D 0.arunrecehed.ml
Radio Frequency Circuit Design - Wiley-IEEE Press Books
This scenario can be generalized for n signal levels in a given signal interval. In general, this study of radio frequency design, the primary focus will be on fundamental hardware design used in transmitters and receivers. Other topics that are of great interest to communica- tion engineers such as programming digital signal processing chips, modulation schemes, and electromagnetic propagation problems are more fully explored in In this book these areas will be referred to only as needed in illustrations of how systems can be implemented.
The pulse train has 16 levels. What is number of levels required? Schwartz, Information Transmission, Modulation, and Noise, 3rd ed.
The simple resistor, capacitor, or inductor cannot be counted on to provide pure resistance, capacitance, or inductance in high-frequency circuits. In addition, when the size of the element becomes larger than 0. Polysilcon, or polycrystalline silicon, consists of many small submicron crystals of silicone with random orientations. In the diffused resistors in a semiconductor substrate, the conductivity is a function of the doping concentration 9 The conductivity is D q nn C pp 2.
In this expression, q is the electronic charge 1. At room temperature it may be assumed that all the impurity atoms in the semiconductor are ionized. This is called the mass action law. The total number of processing steps required in a circuit design often dictates the choice of resistor channel type.
Ideally the diffused resistor with conductivity can be represented by the rectangular block shown in Fig.
Related Radio frequency circuit design
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